Method for loading scouring pads



United States Patent 3,338,742 METHOD FOR LOADING SCOURING PADS Charles F. Swain, Niagara Falls, N.Y., assignor to Union Carbide Corporation, a corporation of New York No Drawing. Filed Feb. 10, 1964, Ser. No. 343,491 6 Claims. (Cl. 117-167) This invention relates to scouring pads. More'particularly, this invention relates to a method for soap-loading scouring pads.

The advantages of a scouring pad containing therein a soap that can be slowly leached out during use are well known, and scouring pads of this type have gained a wide acceptance. conventionally scouring pads are loaded or impregnated with soap by means of an aqueous soap solution which is injected therein or into which a scouring pad is dipped.

From the standpoint of economics and processing expediency, it is desirable that relatively large amounts of soap be introduced into the scouring pad in the shortest possible time. These considerations, in turn, impose certain strict limitations on the soap solution, i.e., that it have a relatively high solids content and, at the same time, a relatively low viscosity which does not interfere with the pad impregnation operations. The viscosity of the solution must be sufiiciently high, however, so that the solution is retained within the scouring pad once it is introduced therein.

Accordingly, it is the principal object of the present invention to provide an improved method for soap-loading of scouring pads.

It is another object to provide a method whereby soaps derived from unsaturated fatty acids can be readily loaded into scouring pads.

A further object of the present invention is to provide a method whereby relatively large amounts of soap can be introduced into a scouring pad essentially in one process step.

Still other objects of the present invention will readily present themselves to the skilled artisan upon reference to the ensuing specification and the claims.

The foregoing objects are achieved by a loading method which comprises providing a solution of a soap derived from a saponifiable fatty acid in a mixture of a lower monohydric alcohol and water. The alcohol and water are present in the mixture in a Weight ratio in the range from about 85:15 to about 3:2, and preferably about 7:3, respectively. If the higher ratio is exceeded insufiicient amounts of water are present in the solvent for retaining the soap in solution whereas if an amount of water is employed which lowers the weight ratio below 3 :2 the soap solution becomes a thick gel which is difiicult to introduce into the scouring pad.

It has been found that the present invention provides a means whereby the soap solids content of a soap solution can be materially increased without a commensurate increase in viscosity. This, of course, greatly facilitates the incorporation of the maximum amount of soap within a scouring pad in the shortest time period. This advantage is particularly apparent with soaps that are derived from unsaturated fatty acids or soaps derived from a mixture of fatty acids, the major portion of which are unsaturated. In addition, scouring pads impregnated in the aforedescribed manner can be dried more easily during the final step of their manufacture because of the relatively greater volatility of the alcohol-Water solvent.

In a further embodiment of the present invention the saponification of a fatty acid and the formation of the impregnating solution can be achieved simultaneously. To this end the fatty acid is dissolved in the lower monohydric alcohol and the saponifying agent is dissolved in water. The relative amounts of alcohol and Water are ice chosen so as to be within the limits hereinabove set forth and the amount of the saponifying agent in the water is such that substantially all of the fatty acid dissolved in the alcohol portion can be saponified.

An additional advantage of this latter embodiment is that the saponification reaction can be completed more quickly in an alcohol-water solution as compared to a Water solution.

The term saponifiable fatty acid as used herein and in the appended claims denotes fatty acids and the glycerides thereof containing from about 10 to about 18 carbon atoms. Both saturated and unsaturated fatty acids are contemplated herein.

Suitable saturated saponifiable fatty acids are illustrated by the following: capric acid, lauric acid, palmitic acid, myristic acid, stearic acid, and the like.

Suitable unsaturated saponifiable fatty acids are illustrated by the following: stillingic acid, A dodecylenic acid, palmitoleic acid, oleic acid, linoleic acid, cetoleic acid, and the like.

Also suitable are animal and vegetable oils which contain a relatively high percentage of a mixture of the abovedefined fatty acids or the saponifiable glycerides thereof. Typical of such oils are palm kernel oil, olive oil, peanut oil, beef tallow, cottonseed oil, corn oil, soybean oil, coconut oil, tall oil, and the like. The oils themselves or the fatty acid-s derived therefrom can be employed. In the latter instance the fatty acids can be both saturated and unsaturated. The resulting mixture of fatty acids frequently bears the name of the oil that the acids were derived from.

The term lower monohydric alcohol as used herein and in the appended claims is taken to encompass the monohydric alcohols having from 1 to 4 carbon atoms, i.e., methanol, ethanol, propanol, isopropanol, and the butanols. For the purposes of the present invention, isopropanol is particularly preferred.

Since the soaps contemplated by the present invention are the salts of fatty acids, the saponifying agent chosen is such that the hydrogen atom of the fatty acid group can be replaced by an alkaline cation supplied by the saponifying agent. Suitable agents for this purpose are the inorganic b ases such as ammonium hydroxide or the alkali metal hydroxides, for example, sodium hydroxide, potassium hydroxide, or lithium hydroxide. Also suitable are the organic bases such as the lower n-alkyl amines, for example, mono-, di-, and tri-ethylamine, mono-, di-, and tri-propylamine, or mono-, di-, and tri-butylamine. In addition the lower alkanolamines can be used, for example, the ethanolamines, the propanolamines, or the butanolamines.

For the formulation of the soap solution, temperature is not overly critical and the compounding can take place over a wide temperature range, for example, from about room temperature to about the boiling temperature of the water-alcohol mixture. A temperature range from about 45 C. to about 70 C. is preferred from the standpoint of viscosity and ease of handling and impregnation.

A Wide variety of scouring pads can be impregnated by the method of this invention. In addition to the conventional steel wool pads, synthetic fiber Web pads, sponge pads, and the like can be subjected to the hereinabove described treatment.

The soap solution can be introduced into the pad conveniently by dipping the pad in the soap solution. The consistency of the solution is such that it is readily retained by the fibers of the pad and will not leak out. However, other methods of impregnation such as spraying of the pad or injection of the solution into the center portion of the pad through a needle can be utilized as well.

The solution can be introduced into the pad at any convenient temperature, preferably at a temperature in the range from about 45 C. to about 70 C. Such elevated temperatures are desirable because of a somewhat reduced viscosity of the solution. Also, the subsequent drying of the pad can be carried out more readily. After the soap solution is introduced into a scouring pad, the pad is subjected to a drying step so as to drive off the solvent and to immobilize the soap within the scouring pad. Drying can be conveniently achieved in open air at elevated temperatures or by a blast of forced hot air.

The present invention is illustrated by the following example.

Example I Tall oil fatty acids (about 700 parts by weight) and coconut oil fatty acids (about 300 parts by weight) were dissolved in isopropanol (about 520 parts by weight) at about 60 C.

Sodium hydroxide (about 150 parts by weight) was dissolved in water (about 240 parts by weight) at about 60 C.

The two resulting solutions were combined while at about 60 C. by adding the alcohol solution to the water solution and stirring. A clear liquid solution having a solids concentration of about 56.8 percent was obtained. The viscosity of the resultant solution was 55.0 centipoises at 50 C., as indicated by a Brookfield viscosimeter, #2 spindle, 60 r.p.m.

Steel wool and synthetic fiber web scouring pads were dipped into the solution once, withdrawn, and dried at about 27 C. for about 24 hours. The finished pad contained about 6 to 7 grams of soap. Similar results were achieved by drying an impregnated pad at about 60 C. for about 60 minutes.

In contradistinction to the above example, the same soap formulation was prepared using only water as the solvent. The actual procedure and the results are set forth in the example below.

Example II Sodium hydroxide (about 150 parts by weight) was dissolved in water (about 3000 parts by weight) at about 60 C. To this solution were added tall oil fatty acids (about 700 parts by weight) and coconut oil fatty acids (about 300 parts by weight) while the solution was agitated and maintained at about 60 C.

A clear liquid solution resulted having a solids concentration of about 27% but a viscosity of 63.0 centipoises at 50 C., as indicated by a Brookfield viscosimeter, #2 spindle, 60* r.p.m.

Steel wool and synthetic fiber web scouring pads were dipped into the solution once, withdrawn, and dried at about 27 C. for about 24- hours. The finished pad contained about 3 to 3.5 grams soap.

From a comparison of the above two examples, it is readily apparent that about twice as much soap can be introduced into a scouring pad when the instant method is employed.

The foregoing discussion and examples are intended as illustrative only. Other modifications and variations can be resorted to by one skilled in the art without a departure from the spirit and scope of this invention.

I claim:

1. A method for loading scouring pads with soap which comprises providing a solution of a fatty acid soap in a mixture of a lower monohydric alcohol and water, the weight ratio of alcohol to water in the mixture being in the range from about 8.5 :1.5 to about 3:2, respectively, introducing the solution into a scouring pad, and thereafter drying the scouring pad to remove substantially all of the alcohol and water.

2. A method for loading scouring pads with soap which comprises dissolving a saponified fatty acid in a mixture of about 7 parts by weight of a lower monohydric alcohol and about 3 parts by weight of water, introducing the resulting solution into a scouring pad, and thereafter drying the scouring pad to remove substantially all of the alcohol and water.

3. A method for loading scouring pads with soap which comprises dissolving a saponified fatty acid in a mixture of about 7 parts by weight of isopropanol and about 3 parts by weight of water, introducing the resulting solution into a scouring pad, and thereafter drying the scouring pad to remove substantially all of the alcohol and water.

4. A method for loading scouring pads with soap which comprises dissolving a saponifiable fatty acid in a lower monohydric alcohol containing from 1 to 4 carbon atoms; combining the alcohol solution with an aqueous solution of an alkaline saponifying agent, the relative amounts of alcohol and water in the combined mixture having an alcohol-to-water weight ratio in the range from about 8.5 :1.5 to about 3:2 and the amount of saponifying agent present being sufiicient to saponify the fatty acid present; introducing the resulting solution of a saponified fatty acid into a scouring pad; and thereafter drying the scouring pad to remove substantially all of the alcohol and water.

5. A method for loading scouring pads with soap which comprises dissolving a mixture of saponifiable fatty acids, the major portion of which is unsaturated fatty acids, in isopropanol; combining the isopropanol solution with an aqueous solution of an alkali metal hydroxide at a temperature in the range from about 45 C. to about C.; introducing the resulting solution of saponified fatty acids into a scouring pad; and thereafter drying the scouring pad to remove substantially all of the isopropanol and water; the relative amounts of isopropanol and water being combined in a weight ratio of about 7:3, and the amount of alkali metal hydroxide present in the aqueous solution being sufiicient to saponify the fatty acids dissolved in isopropanol.

6. A method for loading scouring pads with soap which comprises dissolving about 700 parts by weight of tall oil fatty acids and about 300 parts by Weight of coconut oil fatty acids in about 520 parts by weight of isopropanol; dissolving about parts by weight of sodium hydroxide in about 240 parts by weight of water; combining the resulting isopropanol and water solutions at a temperature in the range from about 45 C. to about 70 C. and under agitation so as to produce a clear liquid solution; impregnating a scouring pad with the clear liquid solution; and thereafter drying the impregnated scouring pad to remove substantially all of the isopropanol and water.

1 References Cited UNITED STATES PATENTS 2,240,114 4/1941 Field 252-91 2,896,242 7/ 1959 Winch 25291 3,112,219 11/1963 Politzer et al. 15-506 3,115,425 12/1963 Zrnoda 252-91 ALFRED L. LEAVITT, Primary Examiner.

RALPH S. KENDALL, Examiner.

A. H. ROSENSTEIN, Assistant Examiner. 

1. A METHOD FOR LOADING SCOURING PADS WIT SOAP WHICH COMPRISES PROVIDING A SOLUTION OF A FATTY ACID SOAP IN A MIXTURE OF A LOWER MONOHYDRIC ALCOHOL AND WATER, THE WEIGHT RATIO OF ALCOHOL TO WATER IN THE MIXTURE BEING IN THE RANGE FROM ABOUT 8.5:1.5 TO ABOUT 9:2, RESPECTIVELY, INTRODUCING THE SOLUTION INTO A SCOURING PAD, AND THEREAFTER DRYING THE SCOURING PAD TO REMOVE SUBSTANTIALLY ALL OF THE ALCOHOL AND WATER. 